Combination fuse and current limiting resistor



March 28, 1933. SANDlN 1,902,902

CO MBINATION FUSE AND CURRENT LIMITING RESISTOR Filed June 16, 1928 INVENTOR Jerome Sandm ATTORNEY Patented Mar. 28, 1933 UNITED STATES PATENT OFFICE JEROME SANDIN, 0] EAST PITTSBURGM, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA GJMIBINA'IION FUSE AND CURRENT LIMITING RFSISTOR Application filed June 18, 1928. Serial No. 285,799.

My invention relates to high-potential fuses and more particularly to current-limitin resistors therefor.

otential-transformer fuses are employed for the protection of potential transformers. Such fuses may be applied without protective resistors in localities where the impedance of the line between the fuse and the generator which supplies current suflices to limit the short-circuit current of the line to such value that the fuse can successfully interrupt it.

In case the fuse is located at such point of a circuit that the possible short-circuit current exceeds the interrupting capacity of the fuse, a current-limiting resistor should be employed in series with the fuse. Such limiting resistors restrict the power that the fuse will be called upon to interrupt in case of a short circuit or over'loadto such value that the fuse will safely interrupt the circuit. By theforegoing arrangement, the high-resistance protective apparatus on the secondary side of the transformer may be eliminated, thereby removing a cause of error in measurement of power in the secondary network circuit.

One object of my invention is to provide a fuse having a current-limiting resistor in series therewith that shall be mounted in such manner that changes may be made in the as sembly thereof in accordance with the space availablefor mounting in the field.

Another object of my invention is to provide a fuse mounted on a pair of insulating members with a current-limiting resistor connected in series therewith without the necessity for providing an additional insulator for mounting the resistor.

My invention comprises, in general, a fuse,

1 that is mounted in series with a currentlimiting resistor 2, both of which are mounted on a pair of insulating members 3 and have attached to the ends thereofthe terminals 4 to which the line conductors, in which the member 7. The insulating member 7 has end caps 8 of conducting material attached to each end thereof and connected in circuit with the .on a channel bar 14 by bolts 15; or may be mounted directly, by the same bolts, upon any structure by which they are to be sup ported. A fuse clip 16, as shown in Fig. 2, is mounted, in the ordinary manner, directly on the .top of the lower insulator 3, and a fuse clip 17, on the upper insulator 3, is supported on 'an extension 18 thereof in order that the bracket 11 may also be mounted on insulator 3 by a bolt 19. In this arrangement, the fuse clip 4 on the first-mentioned insulator 3 is mounted in the usual manner, while the other terminal 4 is connected directly to the upper end of the resistor 2 by a bolt 21. In either case, the resistor is connected in series with the fuse between the two terminals' l.

The object of thus arranging the supporting member 11 and thefuse clips 13, 16 and 17 is to provide a structure in which a resistor may be connected in series with the fuse without the necessity of employing an additional insulator which would require additional space, as well as increase the cost of the apparatus. By providing brackets of the form shown herein, I am able to reduce the head room by mounting the resistor coaxiall'y with the'upper insulating member and connecting the fuse directly across from the end of the resistor to the lower insulating member, as shown in Fig. 1. If, however, the space directly in front of the assembly is limited, but space at the ends thereof is available, an arrangement like that shown in Fig. 2 may be employed. Such a change involves only the substitution for the fuse cli s 13 of fuse clips of the form indicated by re erence characters 16 and 17 and the provision of the bracket 11. It will thus be seen that I have provided means for adding a resistor to the circuit in series with a high-potential fuse without increasing the space occupied thereby or the cost thereof. My invention is further novel in that it supplies two types of fuse-clip supports and a bracket so arranged that the resistor may be mounted to best utilize the space available in different directions thereabout. I do not wish to be restricted to the particular structure and arrangements herein shown, as additions, 'subtractions and Chf'lgBS may be made without departing from the scope of my invention, asset forth in the appended claims.

' I claim as my invention:

1. A fuse structure comprising a fuse, a'

pair of insulating supports therefor and a resistor in series with the fuse and mounted coaxial with oneof said supports.

2. The combination with a fuse, of a pair of insulating supports therefor, a resistor, an insulating member therefor mounted coaxial with one of said supports and means for mounting the fuse between the other end of the resistor and the other support.

3. The combination with a fuse, of a pair of insulating supports therefor, a resistor mounted on one support and constituting an extension thereof.

4. In combination, a resistor, a fuse con.- nected in series therewith and a pair of insulators one of which is coaxial with Said resistor and constitutes a support for it and the fuse.

5. A fuse, a current-limiting resistor for supporting one end of said fuse, and an imsulator for supporting said fuse and said resistor and constituting a prolongation of the latter.

6. In a fuse structure, a pair of insulators, a current-limiting'resistor mounted on one insulator and constituting a prolongation thereof, and a fuse in series. with the resistor and mounted on the other insulator.

a 7. In a fuse structure, a pair of insulators,

a current-limiting resistor mounted on one msulator and constituting a prolongation thereof, supporting means fora fuse on one end of the resistor and on the other insulator, and a fuse bridging the supporting means and connected in series with'said resistor.

8. In combination, an insulator having a live terminal member mounted thereupon, a res stor unit comprising a relatively short hndrical body of insulationhaving metal- .lic end pieces thereupon and having a wire resistance mounted on the body and connected between said end pieces, one ofsaid end pieces being rigidly mounted uponsaid terminal and insulated from ground by said first insulator and a second live terminal for the other .end piece.

resistor is connected, a fuse clip connected to one of the end pieces, a line clip connected to the other piece, and a high voltage insulator supporting the unit and insulating it from ground.

10. In combination, an insulator having a live terminal member mounted thereupon, a resistor unit comprising a relatively short cylindrical body of insulation having metallic end pieces thereupon and having a wire resistance mounted on the body and connected between said end pieces, one of said end pieces being rigidly mounted upon said terminal and insulated fromground by said first insulator and a second live terminal for the other end piece, fuse receiving means supported from said live terminal on said first insulator and a second fuse receiving means mounted on another insulator.

' 11. Aresistance unit comprising a supporting insulator, a resistor wound around said insulator, metallic end pieces to whichithe resistor is connected, a fuse clip connected to one of the end pieces, a line clip connected to the other piece, and a high volta e insulator supporting the unit and insu ating it from ground with said fuse clip supported from between said high voltage insulator and said insulator on which the resistor is wound.

having an insulating body separate from said fuse and fixedly mounted solely from one of said live terminal members and havin one end electrically connected thereto, and

the other end of said resistor having a line terminal member thereon, v

In testimony whereof, I have hereunto subscribed my name this 12th day of June 1928.

JEROME SANDIN. 

